WO2008080595A2

WO2008080595A2 - Hip joint prosthesis

Info

Publication number: WO2008080595A2
Application number: PCT/EP2007/011406
Authority: WO
Inventors: Reinhold Ganz; Michael Leunig; Peter Wehrli
Original assignee: Plus Orthopedics Ag
Priority date: 2006-12-29
Filing date: 2007-12-21
Publication date: 2008-07-10
Also published as: WO2008080595A3; DE102006062618A1; ES2554712T3; EP2106249A2; EP2106249B1

Abstract

The invention relates to a hip joint prosthesis (13) consisting of a metallic outer shell (10) and an inlay which can be anchored in the outer shell (10) and has an articulating or bearing surface for a femoral condyle. The outer shell comprises, at least at the front, a recess (15, 16, 17) extending beneath the equatorial plane (14) of the shell. The neck of the femur can be moved in said recess in a collision-free manner.

Description

"Hip prosthesis"

Description

The present invention relates to a hip joint prosthesis comprising a metal outer shell and an inlay anchorable in the outer shell, which comprises an articulating or bearing surface for a femoral condyle. Furthermore, the present invention also relates to a hip joint prosthesis with only one integral joint shell with articulating surface for a femoral condyle.

Such hip joint prostheses are well known. In this regard, reference is made, by way of example only, to EP 0 346 270 A1 or US Pat. No. 5,916,270 (Lipman), measures being proposed in the latter case in order to avoid the risk of dislocation of the condyle due to a collision (impingement) between hip prosthesis neck and socket edge. at least reduce. These measures are that the adjoining the articulating surface peripheral edge is chamfered from the inside out.

The risk of dislocation also exists after a so-called "resurfacing", ie after making a surface replacement for the natural sliding or articulation surfaces of the acetabulum and the femoral head, because after such a "resurfacing" the head diameter femoral neck ratio is changed, and usually detrimental to the risk of dislocation.

It is an object of the present invention to provide a hip joint prosthesis, in particular a joint shell, in which the abovementioned disadvantages are avoided, with which in particular the risk of an impermissible "impact" ment "between the femoral neck and the edge of the pan is avoided or reduced, even after a so-called" resurfacing ". Furthermore, the invention is intended to avoid a soft tissue injury by "impingement." It is also necessary to reduce the risk of injury to the psoas neck by friction movement over the edge of the socket to achieve as obtained with so-called 180 ° pans high primary stability. It is therefore necessary a pan with optimized ROM, improved primary stability and high variability in their use _^ to make available.

This object is achieved by the measures of claim 1, wherein advantageous embodiments and structural details are described in the subclaims. Characterized in that the outer shell and / or the associated inlay, or in the event that the joint shell is integrally formed, this preferably at least anterior has a below its or below its equatorial plane extending recess, the femoral neck can move into this recess without collision , The risk of a collision or a so-called "impingement" then no longer exists.The recess provided according to the invention also does not impair the primary stability of the acetabular cup.This also applies, in particular, to so-called flat profile pans which extend over less than 180 ° Due to the reduced

Impingement danger is naturally reduced in a corresponding manner, the risk of dislocation or completely avoided.

Preferably, the outer shell has at least two recesses, such that it is suitable for implantation both left and right.

The inlay can be recessed in the same way. It is also conceivable to omit only the inlay, starting from the peripheral edge of the articulating surface. The abovementioned measures also apply to a one-piece shell of at least in the region of the articulating surface abrasion-resistant plastic, e.g. highly cross-linked polyethylene, ceramic or metal. The corresponding material must of course be compatible with the human.

According to the invention, the recesses are in the critical for the range of motion (ROM) zones. In between are preferably segments which are part of a 180 ° pan, so that a high primary stability is ensured in the acetabulum. As already mentioned, the arrangement of the recess (s) / segments is preferably such that that a symmetry results, whereby the same pan right and left can be used.

The segments disposed between the recess (s) may extend to or preferably above the equatorial plane. However, it is also conceivable that at least one of these segments lies below the equatorial plane.

A particularly advantageous embodiment of the invention is characterized in that the outer shell has three approximately uniformly distributed over the circumference arranged recesses, one of which is deeper and longer than the other two. The same applies to an assigned inlay or a one-piece shell, if such an alternative is to be provided.

With regard to preferred ranges of the depth and angular extent of both the recesses and the segments lying between them, reference is made to claims 5 and 6 or 15 and 16.

With regard to a preferred range for an elevation of the at least one segment is made to the claims 8 and 18, respectively.

The outer surface facing the bone is preferably macrostructured, in particular provided with a macrostructured layer. This promotes the connection between the shell or joint socket and the natural bone.

With regard to the definition of a flat profile shell on the one hand and solid profile shell on the other hand, reference is made to claim 10, according to which the meridian of a solid profile shell extends over 180 °, while the meridian of a flat profile shell extends over less than 180 °, e.g. extends only 145 ° or 150 °.

An advantageous imple mentation form is still characterized in that the wall thickness of the outer shell and / or the inlay or in one-piece design of the shell, the wall thickness of these starting from the pole of the articulating surface in the direction radially outward or toward the equatorial surface stepwise or continuously increases. It is therefore essential in this embodiment that the distance between the articulating surface and the outer surface at each pole is smaller than that in the equatorial plane. It should be pointed out again at this point that the measures according to the invention equally apply to a modular shell on the one hand and a one-piece or mono-block shell on the other hand.

Below, preferred embodiments of an inventive hip joint prosthesis or an associated socket will be described in more detail with reference to the accompanying drawings. These show in:

1 a, 1 b and 1 c show a first embodiment of an outer shell according to the invention for a hip joint prosthesis in different perspective views;

2a is a simplified side view of an acetabular cup or

Shell for representing the equatorial plane;

2b shows a further embodiment of an embodiment of an inventive hip joint socket or shell, in particular outer shell in side view, showing three different recesses and segments in between;

FIG. 2c shows the shell according to FIG. 2b in plan view; FIG.

FIG. 3 shows a shell modified from the shell according to FIGS. 2b, 2c with an inflated segment between two adjacent recesses, in a side view;

4 shows an inlay for a modular acetabulum or shell in plan view; and

Fig. 5 shows a further modified acetabular cup or shell or an associated inlay in longitudinal section.

FIGS. 1a, 1b and 1c show a first embodiment of a hip joint prosthesis designed according to the invention, consisting of a metal outer shell 10 and an inlay which can be anchored in the outer shell 10 and not shown here, which comprises an articulating or bearing surface for a femoral condyle. An associated inlay or a preferred embodiment of such an inlay is shown in FIG. 4 represented and designated by the reference numeral 12. The articulating or bearing surface for a femoral condyle has the reference numeral 11. The overall reference numeral for the modular or one-piece hip joint prosthesis or socket is the reference numeral 13.

According to FIGS. 1 a, 1 b, 1 c, the outer shell 10 has three recesses 15, 16 and 17 each extending below or below its equatorial plane 14 (see also FIG. 2 a), into which a femoral neck can be moved without collision.

In Fig. 2a, the equatorial plane 14 is shown schematically. The arrow 18 points in the direction above and the arrow 19 in the direction below the equatorial plane 14. Incidentally, Fig. 2a shows only schematically a hip joint prosthesis 13 in side view. Fig. 2a essentially serves only to explain the equatorial plane and the area above and below it. Further, Fig. 2a schematically illustrates a 180 ° pan. the meridian with the radius "R" extends over 180 °.

The edge 20 of the outer shell 10 extends between the recesses 15, 16 and 17 either in, under or over the equatorial plane 14; In this regard, further details will be given with reference to FIGS. 2 b, 2 c and 3.

As can be seen from FIGS. 1 a, 1 b and 1 c, as well as FIGS. 2 b and 2 c, the three recesses 15, 16 and 17 are distributed approximately uniformly over the circumference. The angular distance is thus about 120 °. One of the three recesses, namely the recess 17, is deeper and longer than the other two recesses 15, 16.

According to FIG. 2b, the dimensions of the largest recess 17 in comparison to the two smaller recesses 15, 16 with an overall height "d" of the outer shell 10 are as follows:

a) depth (x) of the largest recess 17: 0.02 d <x <0.4 db) depth (y) of the smaller recesses 15 and 16: 0.02 d ≤ y ≤ 0.2 dc) (angle) Extension (v) of the largest

Recess 17 over the circumference: 90 ° <v <165; ^C od) (angular) extent (w) of the smaller recesses 15, 16 over the circumference: 40 ° ≤ w ≤ 70 ° ^C ° The segments (Se) or edge regions of the outer shell 10 between the recesses 15, 16, 17 extend over an angular range (s) of 5 ° ≦ s <270 °.

According to Fig. 2c, the angular ranges (w) for the recesses 15, 16 are each about 45 ° to 50 °, while the angular range (v) over which the largest recess 17 extends, is about 100 °.

In the embodiment according to FIG. 3, one of the segments (Se) is raised between the two recesses 15, 16 with respect to the equatorial plane 14, the elevation (Z) being in the range of 0.02 d <Z <0.2 d ,

As stated above, the depth and length of the recesses 15, 16, 17 may be different. The same applies to the shape of the recesses.

Also, the elevation and the length of the arranged between the recesses segments or edge regions can be designed differently. Ultimately, this depends on the preferred adaptation to a given anatomy, and also on the primary stability to be achieved. This is especially true for so-called flat profile pans or dishes.

The inlay 12 can either be recessed in accordance with the outer shell 10. Alternatively, it is also conceivable to save only the inlay 12, wherein the recess in both variants emanates in each case from the peripheral edge 21 of the articulating surface 11. FIG. 4 schematically shows such an inlay in plan view, wherein the aforementioned recesses in the inlay are identified there by the reference numerals 22, 23 and 24. The recess 24 is designed to be larger in terms of its angular extent and depth than the two remaining recesses 22, 23. Insofar, the formation of the recesses 22, 23 and 24 coincides with the above-described recesses 15, 16 and 17 of the outer shell 10th

With regard to the dimensions of the recesses 22, 23 and 24 in the inlay at an overall height (d ') of the inlay 12, it should be noted that the dimensions of the largest recess 24 compared to the two smaller recesses 22, 23 are as follows:

a) Depth (x ³ ) of the largest recess 24: 0.02 d '<x'<0.4 d 'b) Depth (y') of the smaller recesses 22, 23: 0.02 d '<y'<0 , 2 d ' c) (angular) extension (v ') of the largest

Recess 24 over the circumference: 90 ° <v '<165 ° d) (angular) extent (w') of the smaller

Recesses 22, 23 over the circumference: 40 ° <w '<70 °.

Also in the inlay, the segments (Se ') or edge regions between the recesses 22, 23, 24 extend over an angular range (s') of 5 ° <s' <270 °.

Also, at least one of the segments (Se ') may be inflated relative to the equatorial plane, in which case the elevation (Z') is in the range of 0.02 d '≤ Z' ≤ 0.2 d '.

Finally, the recesses 22, 23, 24 not only different lengths and depths, but also be shaped differently or curved. The same applies to the segments (Se ') arranged between the recesses.

As already stated above, outer shell 10 and inlay 12 can be modular, but also in one piece or as a monobloc, as described e.g. in Fig. 5 is shown. In this case, Fig. 5 shows yet another advantageous feature, which may have all forms of leadership if necessary. This feature is characterized in that the wall thickness of the shell 13, starting from the pole (P) of the articulating surface 11, increases continuously in the direction radially outward or in the direction of the equatorial surface 14. A gradual increase in the wall thickness is conceivable.

In a modular design, this measure may relate to the outer shell 10 or only the inlay 12 or both components.

As also stated in the introduction, the component 11 comprising the articulating surface is made of a polymer, in particular polyethylene, ceramic or metal. Ultimately, this depends on the desired pairing between the articulating surface on the one hand and the complementary condyle on the other. Since this is a matter of known measures, a further embodiment is unnecessary.

The same applies to the macrostructuring of the bone-facing outer surface of the described acetabular cup. This can also be obtained by a macrostructured coating. All features disclosed in the application documents are claimed as essential to the invention insofar as they are novel individually or in combination with respect to the prior art.

reference numeral

10 outer shell

11 articulating surface

12 inlays

13 hip joint prosthesis or cup

14 Equatorial plane

15 recess

16 recess

17 recess

18 arrow

19 arrow

20 edge or segment

21 peripheral edge

22 recess (inlay)

23 recess (inlay)

24 recess (inlay)

Claims

claims

1. Hip joint prosthesis (13) consisting of a metal outer shell (10) and an outer shell (10) anchored inlay (12), which comprises an articulating or bearing surface (11) for a femoral condyle, characterized in that the outer shell ( 10), preferably at least anteriorly has a below its or below its equatorial plane (14) extending recess (15, 16, 17) into which a femoral neck collision-free hineinbewegbar.

2. A hip joint prosthesis according to claim 1, characterized in that the edge (20) of the outer shell (10) between the at least one recess (15, 16, 17) extends in, under or above the equatorial plane (14).

3. hip joint prosthesis according to claim 1 or 2, characterized in that the outer shell (10) has at least two non-diametrically opposed recesses (15, 16, 17), such that it is suitable for implantation both left and right.

4. hip joint prosthesis according to one of claims 1 to 3, characterized in that the outer shell (10) arranged distributed approximately three uniformly over the circumference

Recesses (15, 16, 17), wherein preferably one of them is deeper and longer than the other two.

5. hip joint prosthesis according to claim 4, characterized in that at an overall height (d) of the outer shell (10) the dimensions of the largest recess (17) compared to the two smaller recesses (15, 16) are as follows: a) depth ( x) of the largest recess (17): 0.02 d <x <0.4 db) Depth (y) of the smaller recesses (15, 16): 0.02 d <y <0.2 dc) (angle) Extension (v) of the largest recess (17) over the circumference: 90 ° <v <165 ° d) (angular) extension (w) of the smaller

Recesses (15, 16) over the circumference: 40 ° <w ≤ 70 °.

6. hip joint prosthesis according to claim 4 and / or 5, characterized in that the segments (Se) or edge regions of the outer shell (10) between the or the recesses (15, 16, 17) over an angular range (s) of the fifth ° ≤ s ≤ 270 °.

7. Hip joint prosthesis according to one of claims 4 to 6, characterized in that at least one segment (Se) or edge region between the at least one recess (15, 16, 17) relative to the equatorial plane (14) is increased.

8. hip joint prosthesis according to claim 7, characterized in that the elevation (Z) of the at least one segment in the range of

0.02 d ≤ Z <0.2 d.

9. hip joint prosthesis according to one of claims 4 to 8, characterized in that the depth, length and shape of the recesses (15, 16, 17) are different, as well as the elevation and length of the interposed segments or edge regions of the outer shell ( 10).

10. hip joint prosthesis according to one of claims 1 to 9, characterized in that the outer shell as a solid profile shell (extending meridian over 180 °), or as

Flat profile shell (meridian less than 180 °) is formed.

11. Hip joint prosthesis, in particular according to one of claims 1 to 10, characterized in that the inlay (12) either according to the outer shell (10) recessed, or that only the inlay (12), starting from the peripheral edge (21) of the articulating Surface (11) is recessed.

12. A hip joint prosthesis according to claim 11, characterized in that the peripheral edge or the segment (Se ') of the inlay (12) between the at least one recess (22, 23, 24) extends in, under or above the equatorial plane (14) ,

13. hip joint prosthesis according to claim 11 or 12, characterized in that the inlay (12) has at least two recesses (22, 23, 24), such that it is suitable for implantation both left and right.

14. hip joint prosthesis according to one of claims 11 to 13, characterized in that the inlay (12) has three approximately uniformly distributed over the circumference arranged recesses (22, 23, 24), wherein one (24) thereof deeper and longer both circumferentially - As well as radial direction is formed as the other two.

15. hip joint prosthesis according to claim 14, characterized in that at an overall height (d ') of the inlay (12), the dimensions of the largest recess

(24) compared to the two smaller recesses (22, 23) are as follows: a) depth (x ') of the largest recess (24): 0.02 d'<x'<0.4d' b) depth (y ') of the smaller recesses (22, 23): 0.02 d'<y'<0.2d' c) (angular) extent (v ^J ) of the largest recess (24) over the circumference: 90 ° <v '<165 ° d) (angular) extent (w') of the smaller

Recesses (22, 23) over the circumference: 40 ° <w '<70 °.

16. hip joint prosthesis according to claim 14 and / or 15, characterized in that the segments (Se ') or edge regions of the inlay (12) between the or the recesses (22, 23, 24) over an angular range (s') extend from 5 ° <s' <270 °.

17. hip joint prosthesis according to one of claims 14 to 16, characterized in that at least one segment (Se ') or edge region between the at least one

Recess (22, 23, 24) opposite the equatorial plane (14) is excessive.

18. hip joint prosthesis according to claim 17, characterized in that the elevation (Z ') of the at least one segment in the range of

0.02 d ^* <Z '<0.2 d'.

19. hip joint prosthesis according to one of claims 14 to 18, characterized in that the depth, length and shape of the recesses (22, 23, 24) are different, as well as the elevation and length of the interposed segments (Se ') or Edge areas of the inlay (12).

20. hip joint prosthesis according to one of claims 1 to 19, characterized in that the outer shell (10) and inlay (12) are integrally or modularly formed.

21. hip joint prosthesis according to one of claims 1 to 20, characterized in that the articulating surface (11) comprehensive component consists of a polymer, in particular polyethylene, ceramic or metal.

22. hip joint prosthesis according to one of claims 1 to 21, characterized in that the bone facing the outer surface macro-structured, in particular provided with a macrostructured layer.

23. hip joint prosthesis according to one of claims 1 to 22, characterized in that the wall thickness of the outer shell (10), and / or the inlay (12), or in one-piece design of the shell (13) the wall thickness of the same starting from the pole (P) the articulating surface (11) gradually or continuously increases in the direction radially outward or in the direction of the equatorial surface (14).